The structure of your introduction is fine. You attempt to introduce the theme and then express your opinion. You also briefly introduce the reasons as to why you believe so. That's very good!
However, you have a few issues with sentence structuring and vocabulary;
Television is one of the greatest innovations that we use every day. Besides, watching television has some cons and at the same time has very good pros.
.... this is the opening sentence and therefore it should come with a punch : )
Television is one of the greatest technological innovations in the modern world. However, like many other technologically advanced devises, TV too has its pros and cons.I believe it has done the opposite. I think TV programs are among the popular topics in every day talk as well as a great time for gathering.
... you can present this better;
I believe otherwise; In my opinion, TV programs bring the family together by creating a common forum to discuss about them.In addition Modern TV has smart systems and applications that let you be connected with people.
First, it's true that watching TV takes a lot of your day
...
First, it is true that watching TV consumes a lot of your time that can be spent on doing more constructive things.